Mistakes

Dr Nguyen said he felt terrible when he found out Mr Kay had ended his life and realised in hindsight that he had made mistakes.

"[I felt] terrible of course. I was the only doctor that had seen the patient and potentially it was something l could've prevented, not just whether I could've prevented it but whether I had done my best job," he said.

"I completely believed the patient. I didn't see that risk. Given the history of depression I think a more systematic approach would not lead to me omitting some things in my assessment. I was 100 per cent convinced in what Mr Kay told me.

"In hindsight I shouldn't have placed so much emphasis on what Mr Kay had told me. I should've used the information that was available and put more emphasis on that."

Dr Nguyen admitted he failed to note Mr Kay's history of a major depressive disorder, his previous attempt at self-harm and the trauma the man had experienced from losing his wife and children.

"I think in hindsight those things should've raised alarm bells to me, but again I placed more emphasis on what he had told me at the time. I acknowledge that," he said.

There is ... no time in my career that I would ever make a decision about not just whether to detain a patient but the management of anyone prior to having seen the patient

Dr Thi Nguyen

"I was completely convinced that at the time he wasn't a risk of harm to himself from what he had told me. At that time he didn't display features of a mental health disorder that would allow me to detain him."

Consult

Dr Nguyen also conceded he should have consulted a senior doctor and said he would now do things differently.

Morry Bailes, representing SA Police at the inquest, asked Dr Nguyen about his haste in signing the form.

"I suggest to you that it was a busy night and you had already decided that you weren't going to detain this man based on information you already had in front of you, you adopted the triage nurse's note of a situational crisis," he said.

Dr Nguyen said that was not the case.

"Not at all, there is, again, no time in my career that I would ever make a decision about not just whether to detain a patient but the management of anyone prior to having seen the patient," he said.